Digital-indicating knob-enclosed multi-turn potentiometer

ABSTRACT

A knob-enclosed multi-turn precision potentiometer having at its front end a turns-counting and indicating device effective to furnish an accurate decimal-digit indication of the current position of the potentiometer wiper relative to a zero position at one end of the helical resistance element, the potentiometer having means for permitting instant mounting in a standard aperture in an instrument panel of any of a plurality of standard thickness gages and the indicator means presenting accurate indications of fractions of hundredths of one turn from zero to ten turns to accommodate the full range of operation of a 10 turn precision potentiometer, and the indicator further having simplified means for connection with the potentiometer comprising a serrated plug press-fitted into a receiving bore in a supporting member of the potentiometer.

United States Patent Frey, Jr.

[ Sept. 11, 1973 DIGITAL-INDICATING KNOB-ENCLOSED MULTl-TURNPOTENTIOMETER [75] Inventor: Sydney W. Frey, Jr., Upland, Calif.

[73] Assignee: Bourns, 1nc., Riverside, Calif.

[22] Filed: Jan. 10, 1972 21 Appl. No.: 216,520

[52] US. Cl 116/115, 116/133, 235/103,

338/196 [51] Int. CL. G01p 13/00 [58] Field of Search..1l6/1l5,124,115.5,

R25,674 ll/l964 Hardison et a1, 338/143 Primary Examiner-Louis J. CapoziAtt0rneyFritz B. Peterson [57] ABSTRACT A knob-enclosed multi-turnprecision potentiometer having at its front end a turns-counting andindicating device effective to furnish an accurate decimal-digitindication of the current position of the potentiometer wiper relativeto a zero position at one end of the helical resistance element, thepotentiometer having means for permitting instant mounting in a standardaperture in an instrument panel of any of a plurality of standardthickness gages and the indicator means presenting accurate indicationsof fractions of hundredths of one turn from zero to ten turns toaccommodate the full range of operation of a 10 turn precisionpotentiometer, and the indicator further having simplified means forconnection with the potentiometer comprising a serrated plugpress-fitted into a receiving bore in a supporting member of thepotentiometer.

5 Claims, 9 Drawing Figures PATENTEI] SEP I I I973 SHEU 2 0f 2 mzz .543209876 DIG lTAL-INDICATING KNOB-ENCLOSED MULTI-TURN POTENTIOMETER CROSSREFERENCES In respect of certain features herein disclosed thisdisclosure is related to one or more of co-pending applications, viz:Ser. No. 192,119, filed Oct. 26, 1971 now U.S. Pat. No. 3,723,937,entitled PRECISION PO- TENTIOMETER WITH INDICATOR, AND METHOD, by SydneyW. Frey, Jr., Donald L. Gaa, and Robert W. Tetamore; application Ser.No. 216,470, filed concurrently with this disclosure, entitled JUNC-TURE OF CIRCULAR MEMBERS, by Delbert L. Singleton, Sydney W. Frey, Jr.,and Donald I... Gaa, and application Ser. No. 216,400, filedconcurrently with this disclosure, entitled INSTRUMENT SUPPORTINGDEVICE, by Sydney W. Frey, Jr., and Donald L. Gaa; and application Ser.No. 216,432, filed concurrently with this disclosure entitled IMPROVEDDIGITAL READ-OUT ACTUATORINDICATOR FOR MUL- Tl-TURN SI-IAFTACTUATEDINSTRUMENTAL- ITIES, by Robert E. Gaskill and Sydney W. Frey, Jr.

BRIEF SUMMARY OF THE INVENTION In the prior art, knob-enclosedmulti-turn potentiometers are known, such potentiometers havingclocktype indicating means on the front end thereof for providing avisible indication of the extent of displacement or traverse of thewiper or contact of the instrument along the helical resistance element.Such an integrated instrument is disclosed in detail in U.S. Pat. No.Re. 25,674 for example. In that prior art, one hand or pointer of theclock-like indicator presented the appearance of an hour-hand of a clockand presented an indication of the number of full turns of the contactdisplacement from the zero end of the resistance element; and a longerhand or pointer appeared like a clock minute-hand and presented anindication of fractional parts of a turn of contact displacement aboveand beyond the zero or any full-turn displacement of the contact. Whilethe indications provided are accurate, and by means of an improvementdisclosed in U.S. Pat. No. 3,134,086 all ambiguity between a zeroindication and the indication representing 10 full turns of displacementis eliminated, nevertheless in many instances it is undesirable to haveto read the indications presented by two different pointers or hands andaccordingly it is in those instances preferable to have the indicationpresented as a decimal numerical indication. For example, with the notedprior art indicator for a knob-enclosed potentiometer, the clock-face isin the form of a dial presenting numerical indications from through 9,with intervening fractional parts denoted by divisions similar to'minutedivisions on a clock dial, an operator is required to first note theposition of the fullturns pointer and mentally add to that indicationthe numerical value indicated by the fraction indicator or pointer.Erroneous interpretations occur as a consequence due to erroneous mentalarithmetical operations and/or erroneous visual reading of theindications. Thus it is desirable to have an indicator that is directlyoperated by the rotatable shell that actuates the slider or contact asin the noted prior art instrument, but which presents directly a decimalnumber indication of the contact displacement. The present inventionaccomplishes that result by indicator means that do not rapidly wearwith consequent short effective lifetime and early failure, and whichindicator means are directly driven and operated by the same manuallyoperated cylindrical shell that actuates the potentiometer contact. Theshell, rather than driving the end of a pointer as in the noted priorart, is formed with an internal annular face gear that drives a firstindicator number wheel at a low gear ratio of 5-to-l. The first numberwheel steps a pinion twice each revolution, that is once eachhalf-revolution, of the first number wheel, whereby the first numberwheel presents, via a novel arrangement of decimal number indicia on itsface, a direct indication of hundredths of one revolution of the shelland potentiometer contact, and an indication of fractions of hundredthsof one revolution. A second number wheel, stepped by the interveningpinion through 1/l0 revolution twice during each complete revolution ofthe first number wheel, registers or indicates tenths of a revolution ofthe shell and contact.

A third number wheel is stepped one-tenth of a revolution by the secondnumber wheel, through an intermediate second indexing pinion, once eachrevolution of the second number wheel, and thus registers or indicatesthe number of full turns traversed by the contact from the zero positionof the latter at one end of the helical resistance element. Thearrangement of the number wheels is side-by-side along a common axis,and thus the indicator presents to view an instantly readabledecimal-number indication of the position of the potentiometer contactalong the ten-turn extent of the resistance element. For example, atypical indication is 3.96, indicative of 3.96 revolutions of theactuating shell and traverse of the contact through 3.96 turns along thehelix of the element. As will be made evident, fractional values of H ofone revolution of the contact may be accurately read or estimated, forexample 3.965 may be directly read, and other thousandths values easilyestimated at a glance. Because of the characteristics of the countingmechanism of the indicator, and the unique direct-driving connectionfrom the actuating shell to both the indicator and the contact device ofthe potentiometer, extremely accurate resetting of a previously recordedsetting or adjustment may easily be effected. The potentiometer iscarried in a cage adapted for easy and instant insertion in an aperturein a panel, whereby conventional mounting by nut and washer means isobviated and necessity for simultaneous access to both front and read ofthe panel is overcome. The potentiometer is devised to be secured in thecage with the rotary shell and indicator extending forwardly and fromthe front panel surface, and the terminals extending rearwardly from thecage on the other side of the panel.

That portion of the indicator means that is acutated by the rotatablemanually-operated shell comprises a frame in which the number wheels aredisposed about a body in which index-pinion means are mounted. The framecomprises a keyed rearwardly-extending fluted stub that tightly fits ina complementary bore or hole provided in the central rigid supportmember of the potentiometer. Thus the numerical indicia on theturnscounting and indicating means can readily be phased or aligned withthe mounting means without further adjustment. Phasing of the read-outto the potentiometer contact is accomplished through a manuallyrotatable interlock between the indicator and the potentiometer rotaryshells. The potentiometer is illustrated in preferred form in theaccompanying drawings forming a part of this specification.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a pictorial representation, to noparticular scale, of the potentiometer as mounted in the snap-in cagewith decorative bezel;

FIG. 2 is an enlarged side view of structure of FIG. 1, partly insection and with some parts broken away to reveal details;

FIG. 3 is a transverse sectional view of the indicator mechanism, withactuating knob shell means indicated in phantom;

FIGS. 4, 5, 6 and 7 are sectional views taken as indicated by directors44, 6-6, and 77 in FIG. 3, FIG. being a fragmentary view illustrating alocking feature but otherwise similar to FIG. 4;

FIG. 8 is a pictorial view of a stepping pinion; and

FIG. 9 is a plan view illustrating the arrangement of indicia onnumber-wheels of the indicator.

DETAILED DESCRIPTION OF THE DRAWINGS Referring first to FIG. 1, there isdepicted an assembled device 10 according to the invention, the devicecomprising a snap-in mounting cage or chassis 12 adapted to be pressedinto a dimensioned aperture in an instrument panel and thereby besecured to the panel in a manner and by means fully disclosed andexplained in the previously identified concurrently-filed applicationfor Letters Patent of Sydney W. Frey, Jr., and Donald L. Gaa. Further,the device 10 comprises, secured to the chassis 12, a decorative andfunctionalperforming circular bezel 14, described and explained in theaforementioned concurrently-filed application for Letters Patent ofDelbert S. Singleton, Sydney W. Frey, Jr. and Donald L. Gaa. Further,the device 10 comprises an indicator mechanism of a novel type denotedgenerally by the number 16, the details of which indicator mechanism aredisclosed and described, with the exception of modifications hereindescribed in detail, in the aforementioned application for LettersPatent of Robert E. Gaskill and Sydney W. Frey, Jr., entitled IMPROVEDDIGITAL READ-OUT ACTUA- TOR-INDICATOR FOR MULTI-TURN SHAFT- ACTUATEDINSTRUMENTALITIES. Reference to the above-identified disclosures may bemade if necessary, those disclosures being incorporated herein byreference.

As is indicated in FIG. 2, the chassis 12 comprises a plurality ofresilient limbs such as 12a that are integral with the generallycylindrical body 12b of the chassis at their rear ends and are stressedto spring outwardly after being forced inwardly by cam action on theperipheral circular surface around an aperture Pa in a panel (indicatedin phantom lines an denoted by the letter P in the drawing). The forwardend of the chassis terminates in a radially outwardly extending circularflange 12f the rear face of which is adapted to abut against the frontsurface of the panel P around and outside the aperture Pa. The flange isreinforced and enhanced in appearance by the aforementioned metallicring or bezel 14. The chassis is of generally cup-like formation, havinga circularly-arranged set of stepped holes, such as 12h (FIG. 2), inbottom, in which are received fastening means for securing thepotentiometer support member of the chassis. Further, the bottom of thechassis has a central opening 120 which receives with a close fit arearwardly-extending plug-like extension l6e of the potentiometersupport member 16. The extension has extending therethrough andprotruding therefrom a set of three spaced-apart terminal wires T1, T2and T3, similar to those depicted in the aforementioned US. Pat. No. Re.25,674. The terminal wires are mutually insulated by virtue of theinsulative characteristic of the thermoplastic resin from which supportmember 16 is formed. The support member is originally formed with acircularly arranged series of rearwardly-extending fastener posts 16s(upper right, FIG. 2) each of which is dimensioned and spaced to fit inand extend through a respective one of the holes 12h in the base of thechassis. At the time of assembly of the indicating potentiometer to thechassis, each of the posts 16s is thermoplastically deformed and headedin the enlarged portion of its respective hole, as indicated at 16s atthe lower right in FIG. 2. Since the entire potentiometer and indicatorportion of the device is supported by and upon the support member 16, itis evident that the chassis serves to secure the instrument portion ofthe device securely to the panel.

As is explained in the aforementioned disclosure in the application forLetters Patent of Sydney W. Frey, Jr. and Donald L. Gaa, the limbs ofthe chassis 12, such as limb 12a, are formed with inclined steps asindicated at 12s in FIG. 2, whereby the chassis automatically adaptsitself to panels of a variety of thicknesses.

The multi-turn knob-enclosed precision potentiometer comprised in thedevice 10 includes a helical resistance element 18 mounted in a helicalgroove on the forward end of the support member 16, a rotary generallycylindrical shell 24 and a contact-carrying slider 20 driven along theelement by the shell, and returnconductor means 22, all like or similarto their counterparts or functional equivalents disclosed in Pat. No.Re. 25,674. According to the present invention the support member 16 isproduced with a cylindrical bore 16b in its forward end, the bore beingdimensioned to receive with a tight drive fit the rearwardly-extendingperipherally-fluted plug-like rear end 32f of an indicator support 32.The indicator support 32 is formed with two sets of forwardly-extendingpillars or pedestals 32p shaped to provide a pair of saddles 32s and 32s(FIG. 3) in which are seated a hub 38h of a first number wheel 38presently described, and a shaft or spindle 34;

A circular frame 36 (FIG. 2) is mounted on the forward ends of thepedestals 32p, as by means such as pins 32p (FIG. 3) formed on thepedestals and tightly received in complementary sockets formed in therear face of the frame, or by adhesive or other known fastening means.The frame is fenestrated to provide a window 36w (FIG. 1) through whichnumerical and other indicia may be viewed.

The rotary slider-driving shell 24, as is indicated in FIG. 2, isextended forwardly by an extension or forward shell, 28, that is securedto the rear shell 24, for example, adhesive, or by a tight twist lockstructure as illustrated. The forward shell 28, extending forwardly ofthe panel P, serves the plural functions of providing a manuallyrotatableknob-like structure for rotational manipulation by an operatorin adjusting the potentiometer, of housing and protecting the indicatormechanism of mounting a protective lens, and of driving the indicatormechanism incident to adjustment of the potentiometer.

Mounted on, and carrying one end of spindle 34 (FIG. 3) is a combinedfirst drive pinion and number wheel, 38, the outer end of which isformed as a pinion 38p. Both the hub 38h and the pinion portions ofwheel 38 are received in the seat or saddle 32s. The end of spindle 34(opposite from pinion 38p seats snugly in the saddle 32s, and thus thespindle is retained in a stable attitude, and in a mutually-aidingrelationship, stabilizes wheel 38 in a rotational attitude for rotationabout the axis of the spindle in a plane perpendicular to the axis.

The first number wheel drive pinion, 38p, is complementary to and isengaged by the teeth 28g (FIG. 3) of a rearwardly-facing driving gearformed on an inner face of shell 28. Thus rotation of. the shell toadjust the contact along the resistance element of the device causesrotation of pinion 38p and number wheel 38. In accord with theinvention, and differing from prior-art practice and construction ofdigital turns-counting mechanisms for otentiometers, such as thatillustrated in US. Pat. No. 2,777,637 for example, the ratio of thenumber of teeth 28g of the driving gear to the number of teeth of pinion38p is 5 to I rather than 10 to l.Thus the first number wheel of theindicator rotates only five revolutions each revolution of shell 28.Several marked and novel advantages accure from this structural change,as wil hereinafter be made clearly evident.

In conventional or prior art digital indicators for precisionpotentiometers, the first number wheel is employed to indicatehundredths of one revolution of the contact, the'second number wheel toindicate tenths of one revolution, and a third number wheel to indicateindividual complete revolutions, up to and including 10 revolutions.Additional number wheels are employed for potentiometers having morethan 10 turns or convolutions of the resistance element. In the presentinvention a l-turn resistance element is employed, and hence threenumber wheels, 38, 40 and 42 are used (FIG. 3). Further, since the ratioof revolutions of the contact and slider to revolutions of shell 28 andgear 28g is 1-to-1, and the ratio of revolutions of gear 28g to pinion38p is 5-to-l, each half revolution of number wheel 38 represents /100of a revolution of the contact along the resistance element.Accordingly, the numerical indicia on wheel 38 are deviced and arrangedto represent 10/100 of one turn of the potentiometer on each half of theperipheral face of that wheel. Such an arrangement of indicia isillustrated in strip form in the right-hand column in FIG. 9, whereinthe indicia strips for each of the three number wheels 38, 40 and 42 areshown as straightened rim faces of those wheels. Therein, the indiciafor wheel 38 are noted to comprise theseriesofnumerals2-4-6-8-0-2-4-6-8-0 and thus to numerically extned twice through the series ofdecima]numbers 0 to 10. In the interest of readability in the small-diameterdevice illustrated in the drawing, the odd numerals of the decimalseries are omitted and a short line substituted for each odd number, asindicated in the right-hand column in FIG. 9. intermediate lines, asindicated in the drawing, are provided to facilitate reading or settingof the potentiometer to fractional values less than 1/100 of onerevolution of the contact.

As is indicated in FIG. 1, a ledger or index line L is provided on thefront face of member 36, aligned with the center of the window 36w anddisposed for registry with the number-representing lines on wheel 38, tofacilitate instantaneous visual reading of the value pres- -ented by thenumber wheels.

Since each half-revolution of first number wheel 38 represents a fulltenth (10/100) of one revolution of shell 28, provision is made forindexing or stepping the second number wheel one step (one tenth of arevolution) during each half-revolution of the first number wheel. As isshown in FIG. 3, the second and third number wheels, 40 and 42, areformed as rings presenting cylindrical indicia-bearing outer faces andinternal faces presenting at one end a continuous set of gear teeth. Thewheels 40 and 42 encircle a hollow carrier 44 whose interruptedcylindrical surface provides a bearing surface on which the wheels maybe rotated and on which they are disposed in end-to-end stacked relationrelative to wheel 38, as is common in revolution-counting mechanisms.The carrier is formed with a bore 44b at its inner flanged end, in whichbore one end of spindle 34 is received. Thus the carrier is supported bythe spindle, suspended between the flange end of number wheel 38 at oneend and the pillars 32p at the other end. The carrier has an outstandingprojection 44k (FIG. 3) that is received in a complementary recess inthe inner face of frame 36, the arrangement providing alignment of thenumerals with window 36w and preventing rotation of the carrier onspindle 34.

The carrier 44 is provided with aligned bores in which is tightlycarried with a press fit an index-gear shaft 46 (FIG. 3) on which aresupported for free rotation first and second indexing gears or pinions48 and 50 of like form and shape as shown in FIG. 8 wherein only pinion48 is shown. Pinion 48 comprises a sixtooth output ornumber-wheel-driving section 480, and a six-tooth central input portion48b alternate teeth of which are shortened and formed with oppositelyinclined faces such as 48c and 48d that are configured to coact with aninterrupted circular inner flange face of a respective number wheel, forexample face 38f on wheel 38 depicted in FIG. 5. Hence the inclinedfaces are effective to lock the pinion against undesirable rotation, butpermit step-rotation when an input portion tooth thereof is engaged byan internal tooth formation on a preceding or driving number wheel, as,for example, either of the formations 38d on wheel 38 depicted in FIG.4. Clearance for either of the three locking tooth portions is providedin the flange 38f at two opposite locations, such as at 381' in FIG. 4.Thus, for example, the tooth formation 38d, in rotating, engagessuccessively two input teeth of pinion 48 to rotate the latter,the-interruption of flange 38fin the region intermediate the teeth offormation 38d permitting such stepping, and the next succeeding set ofinclined faces of the locking portions of the pinion 'teeth beingbrought into sliding contact with flange 38f as shown in FIG. 5. It willbe noted that the ends of the three pinion teeth intervening betweenthose with inclined faces 48c and 48d are shortened or eliminatedentirely in the plane of flange 38f, to provide clearance for theflange.

The first number wheel 38, is formed or provided with a pair ofoppositely disposed driving-tooth formations 38d, as indicated in FIG.6. The space between the two teeth of either formation is aligned with arespective interruption 38i of the. flange 38f, as previously indicatedand as is shown in FIG. 5. Thus twice during any revolution of wheel 38in either direction a tooth formation such as 38d engages and drives theindex pinion through a two-tooth step. The output portion of the firstindexing pinion 48, comprising the six full-teeth portion 48a (FIG. 8)is engaged continuously with the internal series of teeth on secondnumber wheel 40, as indicated in FIG. 3. That series comprises 20 teeth,hence at each stepping of pinion 48 the second number wheel is advancedl/lO of a revolution to change the indication presented at the centerdigit in window 36w by one decimal digit.

Second number wheel 40 comprises only one twotooth pinion-drivingformation, as indicated in FIG. 7 and accordingly will step the secondindexing pinion 50 only one two-teeth step per revolution. Pinion 50 isat other stages locked by an internal interrupted flange 40f on numberwheel 40, similar to the locking flange of wheel 38 excepting that onlya single interruption, 40i, is provided, aligned with the two-toothdriving formation. Thus at each revolution of wheel 40 the pinion 50advances the third number wheel 42 two teeth, changing theexhibiteddigit in the first (left-hand) number space in window 36w onedecimal digit. The operation of the second indexing pinion 50 and thethird number wheel 42 is like or similar to that of thesimilarly-related components of a conventional revolution counteryandthe operation of the entire rotationcounter and indicator portion of thedevice is substantially the same as that disclosed in the aforementionedapplication of Robert E. Gaskill and Sydney W. Frey,

In the described device, the teeth 28g of the gear portion of extensionshell 28 are 65 in number, and those of pinion 38p of the first numberwheel are 13 in number. Considerable advantages and improvements areprovided and permitted by employment of that S-to-l gear ratio. Thatratio is but one-half the ratio of priorart digital revolution countersand indicators, which used gearing of 10 to 1 ratio. The 5-to-1 ratio isfeasible because of the utilization of first number wheel 38 to register20/100 of one shell revolution, rather than only /100 revolutions as inthe prior art. One advantage of the S-to-l gear ratio arrangement isthat in smalldiameter devices, for example devices less than l inchshell diameter, the first wheel pinion despite having to be of verysmall diameter, can be produced with strong gear teeth of substantiallystandard profile, rather than with weak roots as when only half as manyteeth are used. A second and very important advantage is that wear isreduced by 50 percent since the critical pinion for the first numberwheel rotates only half as much as would the pinion in a l0-to-l gearratio arrangement. A third advantage is that the first wheel pinion canbe larger, for a prescribed shell-gear diameter, which permits of thepinion being formed of thermoplastic material whereas in the prior artthe first pinion was required to be of metal if reasonableoperating-lifetime was to be assured and defective operation clue toexcessive pinion wear avoided. A fourth advantage is that due to theincreased size permitted for pinion 38p and the reduction of wearing by50 percent, with the consequent ability of a thermoplastic pinion tosuccessfully operate satisfactorily throughout a long operatinglifetime, the pinion and first number wheel may be formed as a singleunitary integral part, with a simple dowel pin shaft, rather than asseparate parts of an assembly consisting of a machined metal pinion, ashaft, and a molded number wheel as in the prior art devices. Anotheradvantage afforded by the 5-to-l driving gear ratio is the grossreduction of impact-loading of the indexing pinions and consequentreduction of wear and liability of injury or fracture from such loading.Since impact loading, as when a two-tooth formation of a number wheelsteps a pinion, varies in proportion to the second power of thevelocity, the reduction of the primary drive speed by 50 percent resultsin a reduction of impact loading to about one-fourth of that incurredwith a lO-to-l gear ratio driving arrangement. Thus impact loading andconsequences thereof are by the present arrangement renderedinconsequential. A further benefit is achieved in this assembly with abacklash spring 50 which sets under the indicator support 32 and holdsit in contact with gear 28g. it is thus possible to keep gear mesherrors such as backlash at a minimum without applying the tension, whichwould result in binding and roughness, directly to pinion 38p.

As is evident from the preceding description and the drawings, thesequence of assembly would be as follows. The contact-carrying slider 20is placed in the shell 24 and these are set on the support member 16.The backlash spring 50 is set on top of the shell 24 and the indicatorsupport 32 is pressed into the potentiometer support 16 by forcingsplined stub 32f into the bore 16b. Thereafter the previously assembledindicator mechanism is set into saddles 32s and 32s and the circularframe 36 is pressed onto pins 32p. The lens 30 and forward shell 28 areset on the assembly, engaging gears 28g and 38p and rear shell 24. Dueto the relatively close fit relationship of the parts, it is nowpossible to bring the slider 20 up against a stop on the bottom of theindicator support 32 and adjust the indicator read-out to 0 0 0 byrotating shell 28 while holding shell 24 steady. After an initial checkto quality standards, the splined stub is cemented to the support memberand the cement joint between the shells is filled. Thereafter thepotentiometer and indicator assembly is moved into chassis l2 and posts16s heat-swaged into the ends of holes 12h of the chassis. Bezel 14 isalternatively applied to the chassis before, or following assembly ofthe potentiometer into the chassis, or may be omitted if the addedstrength, etc. is

not necessary. Thus at completion of assembly of the notedsubassemblies, the indicator means are accurately phased with thepotentiometer and the device is ready for easy manual pressing into amounting panel for instant locking thereto.

Having disclosed a preferred embodiment of the invention, I claim:

1. A digital turns-indicating potentiometer device comprising:

first means, including a support means and means for securing the devicein an aperture in an instrument panel; second means, including apotentiometer element and contact-carrier means, supported by saidsupport means; third 1' means, including a decimal digital indicatormeans, supported by said support means and comprising a set of numberwheels at the forward end thereof for presentation of a decimal digitalindication of the extent of traverse of said contact-carrier along saidelement, indexing pinion means connected to said number wheels forstepping said number wheels relative to a preset amount of rotation ofits next adjacent number wheel, and indexing teeth means carried by allbut a last number wheel for engaging said indexing pinion means, a

first of said number wheels including two indexing teeth formations saidtwo indexing teeth formations located diametrically opposed to eachother for stepping a second number wheel through two l/lO revolutionsteps for each complete revolution of said first number wheel; and

fourth means, including rotary shell means disposed around said secondand third means and engaging said contact-carrier to drive the samealong said element, said shell means comprising gear means geared tosaid indicator means to rotate said first number wheel five revolutionsand said contact carrier one revolution for each complete revolution ofsaid shell means and further serving as a knob-like structure adaptedfor manual manipulation for concurrently adjusting said contact-carrierand driving said indicator means to provide a digital numericalindication of the position of said carrier along said element.

2. A device as specified in claim 1, in which said element is amulti-turn helical resistance element disposed on said support means.

3. A device as specified in claim 1, in which said means for securingthe device in an aperture man instrument panel comprises a cup-likestructure having a flange arranged to bear against the front face of apanel with the body thereof extending through and rearwardly of thepanel, said cup-like structure comprising outwardly-stressed resilientlimbs adapted to be forced inwardly while the structure is being pressedinto the aperture and to spring outwardly and engage the panel at therear thereof to secure the structure to the panel, and the said supportmeans being secured to said structure.

4. A device as specified in claim 1, in which said element is a helicalelement disposed on said support means about an axis, and said supportmeans and said indicator means comprise in one a bore along said axisand on the other a projection secured in said bore, whereby saidindicator means is secured to said support means in axial alignmenttherewith.

5. A device according to claim 1, in which said set of number wheelscomprises first second and third number wheels and said indicator meanscomprises means for rotating the second number wheel 1/10 revolutionduring each half-revolution of the first number wheel and for rotatingthe third number wheel 1/10 revolution during each revolution of thesecond number wheel.

UNITED STATES PATENT FFICE CERTIFICATE OF CURRECTION Patent N0-3,757,732 Dated September 11. 1973 Inventor(s) Sydney W. Frey, Ir.

It is certified that error appears in the above identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 4, Line 58, insert -byafter "shell 24''.

Column 5, Line G, "(opposite" should read -opposite--. [remove parenthe-Column S, Line 26, "acoure" should read accrue. Ses] Column 5, I in e"yvi l should read n7i1l--.

Column 5, Line 45; "devioed" should read devised Column- 5, Line 55,"extned" should read --extend--.

Column 10, Line 17; insert after "first".

Signed and sealed this 17th day of December 1974.

(SEAL) Attest: I

McCOY'M. GIBSON JR. I C. MARSHALL DANN Attesting Officer I Comissionerof'Patents FORM PO-lOSO (10-69) Y I I I uscMM Dc 60376456 I I i 0.5.sovnomn'r nnmua owner 1 l9! o-su-su UNI TED S'IATESPATENT FFICECERTIFICATE OF CORRECTION Patent No. 3, 757, 7-32 "Dated September 11,1973 Invent or(s) Sydney Prey, Ir.

It is certified that error appears in the abeve -identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 4, Line 58, insert byafter "shell 2 4".

Colgmnfi, Line6, (o ppes ite" sho uld read -ot pesite-. [removepa'renthei- Column 5, Line' 26,- "accure' sh ould read e came. sesColumn 5, Line sheuld read -L- yr i1 1-. Column 5, Line "de vieed"should read d e vised Co lu i nh- 5, Line 55, "extned" sheuld reed exten d.

Column 10, Line 1?; insert after "first".

Signed and sealed this 17th day of December 1974.

(SEAL) Attest: v

Mccoy GIBSON JR. v r v c. ZARSHALL DANN Attesting officer Comissioner pfPatents FD-RM PO-IOSOH L I I I I uscoQM-oc wade-Pee H

1. A digital turns-indicating potentiometer device comprising: firstmeans, including a support means and means for securing the device in anaperture in an instrument panel; second means, including a potentiometerelement and contactcarrier means, supported by said support means; thirdmeans, including a decimal digital indicator means, supported by saidsupport means and comprising a set of number wheels at the forward endthereof for presentation of a decimal digital indication of the extentof traverse of said contactcarrier along said element, indexing pinionmeans connected to said number wheels for stepping said number wheelsrelative to a preset amount of rotation of its next adjacent numberwheel, and indexing teeth means carried by all but a last number wheelfor engaging said indexing pinion means, a first of said number wheelsincluding two indexing teeth formations said two indexing teethformations located diametrically opposed to each other for stepping asecond number wheel through two 1/10 revolution steps for each completerevolution of said first number wheel; and fourth means, includingrotary shell means disposed around said second and third means andengaging said contact-carrier to drive the same along said element, saidshell means comprising gear means geared to said indicator means torotate said first number wheel five revolutions and said contact carrierone revolution for each complete revolution of said shell means andfurther serving as a knob-like structure adapted for manual manipulationfor concurrently adjusting said contact-carrier and driving saidindicator means to provide a digital numerical indication of theposition of said carrier along said element.
 2. A device as specified inclaim 1, in which said element is a multi-turn helical resistanceelement disposed on said support means.
 3. A device as specified inclaim 1, in which said means for securing the device in an aperture inan instrument panel comprises a cup-like structure having a flangearranged to bear against the front face of a panel with the body thereofextending through and rearwardly of the panel, said cup-like structurecomprising outwardly-stressed resilient limbs adapted to be forcedinwardly while the structure is being pressed into the aperture and tospring outwardly and engage the panel at the rear thereof to secure thestructure to the panel, and the said support means being secured to saidstructure.
 4. A device as specified in claim 1, in which said element isa helical element disposed on said support meanS about an axis, and saidsupport means and said indicator means comprise in one a bore along saidaxis and on the other a projection secured in said bore, whereby saidindicator means is secured to said support means in axial alignmenttherewith.
 5. A device according to claim 1, in which said set of numberwheels comprises first second and third number wheels and said indicatormeans comprises means for rotating the second number wheel 1/10revolution during each half-revolution of the first number wheel and forrotating the third number wheel 1/10 revolution during each revolutionof the second number wheel.